Making a Map site a search engine

I have installed 1 or 2 search engines in Opera just fine, but tonight I wanted to make Bing Maps another search engine. However, when I entered search terms, I found that there was an incredibly long string of characters, and wasn't sure what to delete and what to leave in.

Has anyone here made a map search engine, a search engine in Opera? What steps did you follow? I tried the default URL www.bing.com/maps/ and then added %s. Opera immediately saw, when I attempted a search, that I was wanting to search through bing maps, but the bing results page said the page didn't exist.

Problem is, for some reason it doesn't seem to be working right with Bing Maps. I did what you said--went to the search box, selected the "create search engine" option, and entered a keyword. Now when I hit the keyword, Opera knows that I want to search bing maps, but the result isn't a map. You can see here:

Interesting... I've just tried to do that, no success.
For Yahoo Maps, it seems there's no GET query like maps.yahoo.com/?q=location which would work with arbitrary toponyms, like in Google or Bing.

In MapQuest, I've totally failed to understand how it queries data, and the context menu option 'Add search...' is not available for MapQuest, I don't know why, maybe because there's a jquery-powered form without parseable action url, or for another reason. Can't answer that right away, sorry.